Conventional incandescent bulbs, mercury lamps or light emitting diode lamps, particularly high-power lamps, such as road lamps, spot lights, and large decorative or advertising lamps have the drawbacks of high power consumption, large volume, and high price. As the light emitting diode (LED) technology is well developed, LED has the features of small volume, high efficiency, power saving, and dimmable light, and thus the LED gradually replaces the conventional incandescent bulbs and mercury lamps and becomes a mainstream product of the related market and used extensively in the illumination field.
With reference to FIG. 1 for a conventional road lamp, the road lamp comprises a road lamp pole 10 and a lamp 20, and an end of the road lamp pole 10 is fixed to the ground on a road, and the other end of the road lamp pole is coupled to the lamp 20, and a connecting position 30 of the road lamp pole 10 and the lamp 20 is fixed and cannot be moved or rotated, such that the light of the lamp 20 can be projected to a fixed area 40 below the lamp 20, wherein the lamp 20 can be a conventional incandescent bulb, mercury lamp or light emitting diode, and usually comes with one light emitting diode, and the lamp 20 has the features of high projection efficiency and large projection range, and the lamp 20 can project light to the fixed area 40 in a broad range.
However, the light emitting diode generally has low projection efficiency, so that when the light emitting diode is installed at a higher position, the projection range is very limited, and the projection range of the lamp 20 of the road lamp structure on the fixed area 40 is reduced. If the LED is used as the lamp 20, it is necessary to adjust the fixed area 40 to the desired area effectively. In the meantime, the conventional lamp 20 is fixed to the connecting position 30 and cannot be moved or rotated, so that when the road lamp pole 10 is tilted or bent, the fixed area 40 illuminated by the lamp 20 will be changed and the road lamp will fail to maximize its performance. Now, the only solution is to change the road lamp pole 10 which will waste unnecessary costs and labor.
In view of the foregoing drawbacks of the prior art, the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally overcome the drawbacks of the prior art by providing an LED lamp with adjustable projection angle in accordance with the present invention.